1. Field of the Invention
The invention relates to apparatus for individually dispensing die cut pressure-sensitive labels from a carrier web containing a plurality of such labels. More particularly, the invention relates to a label dispensing machine having detecting means which senses the gap between adjacent labels on the carrier to stop the web at the proper label discharged position, and to a machine which can be adjusted easily to accommodate labels of different lengths.
2. Description of the Prior Art
Various types of label dispensing machines are known in the prior art for dispensing labels from a label train either automatically onto a moving article or manually for placement on an article. Many of these prior machines use various interconnected mechanical components to properly position the label at its discharged position. Other machines use a timing circuit which automatically advances the moving web for a predetermined time period upon the label being dispensed in an attempt to place the adjacent label at the correct label dispensing position. However, problems occur in that the labels are sometimes irregularly spaced on the web and/or a label is missing, which provides a faulty signal to the timing and feed control mechanism. Also, small differences in spacing between the individual labels will accumulate over a period of time, affecting the discharge position of the dispensed label.
Examples of prior label dispensing machines which use electromechanical control means and positioning switches for regulating the movement of the label being dispensed or article having a label applied thereto are shown in U.S. Pat. Nos. 3,029,979, 3,039,516, and 3,169,895.
Various other label dispensing machines and label applying mechanisms control the dispensing operation and/or movement of articles being labeled by the use of various photoelectric sensing means which control either the drive mechanism of the label dispenser and/or the movement of the article. Examples of such constructions are shown in U.S. Pat. Nos. 2,522,224, 2,920,780, 3,193,430, 4,019,935, 4,188,252, U.S. Pat. No. Re. 30,419, U.S. Pat. Nos. 4,239,570 and 4,248,655.
However, none of these prior art machines show a label dispensing machine relatively simple in operation and construction which uses an infrared photoelectric sensing mechanism which senses the density difference between the label and gaps between adjacent labels for controlling a stepping motor having an adjustable actuation time period for advancing the label to the discharge position, and in which control means enable the machine to be used for labels of different lengths.